In this paper we will present methods for displacement characterization of topology optimized electro-thermal microactuators. Although thermal actuators are the object of our research, these methods are general in nature and can be applied for any type of laterally driven actuator. Characterization of these actuators is done by recording the power dissipated in the actuator and, by the use of a framegrabber, grabbing a microscope image of the work-point of the actuator. From the microscope images displacement information is found by image analysis. Using the presented method, displacements can be measured with a resolution of 5 nm. This highly accurate displacement measuring method is used to calculate displacement distributions form which the strain distribution can be calculated.